Distributed generation wind energy systems, particularly in the medium wind market in the range of 10-1,000 kilowatts (kW) of power generation, can make a substantial environmental impact and meet a growing demand for renewable energy. However, such systems are not economical because most distributed generation wind turbines operate at lower heights than utility scale models, and at these heights wind speed is below the minimum speed needed to make energy recovery economically feasible.
The type of turbine commonly used in distributed generation is a vertical axis wind turbine (“VAWT”). Current VAWTs can not translate the energy from airflow through a blade system effectively because the blade systems can not effectively spin at low altitude, under 100 feet, when the blades are required to spin high (MOI) Generator torque requiring electric generators which are 50 kW and larger.
One approach for solving this problem is to alter the design of the wind turbine or its components in an attempt to improve efficiency. Known adjustments include changing the shape of the turbine blades, incorporating an airfoil stator and even boosting efficiency by harnessing other forms of renewable energy such as the sun by adding solar cells to the wind energy system. However, such approaches increase production costs as specialized manufacturing may be required to produce different turbine designs. Adding solar cells also increases the costs of providing and installing the wind energy system.
Other wind energy systems add wind accelerator components to the turbine to increase the airspeed velocity of the air contacting the turbine blades. In one example of such a system, the accelerator is a frusto-conical funnel-like device intended to direct a stream of wind through the device onto the impeller of a windmill. This system has the disadvantage that the funnel-like device is bulky, fragile and unsightly. More significantly, it functions with horizontal access wind turbines, not the vertical axis turbines common in distributed generation applications.
Therefore, there exists a need for an economical distributed generation wind energy system that can work with existing models of vertical axis wind turbines. Specifically, there is a need for a wind energy system that does not require extra or specialized turbine components. In summary, there is a need for a distributed generation wind energy system that employs a wind accelerator to improve efficiency and can work with existing models of vertical axis wind turbines.